The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Rupert Grashey - One of the best experts on this subject based on the ideXlab platform.
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susceptibility weighted angiography visualizes hypoxia in Cerebral Veins
Investigative Radiology, 2015Co-Authors: Maximilian Patzig, Berend Feddersen, Katrin Haegler, Bernhard Olzowy, Klaus Mees, Rainald Fischer, Sven Becker, Ulrich Kisser, Jessica Freiherr, Rupert GrasheyAbstract:OBJECTIVES: The objective of this study was to evaluate the influence of short- and long-term hypoxia on the depiction of Cerebral Veins in the susceptibility-weighted angiography (SWAN) sequence. MATERIALS AND METHODS: In the context of a study on brain adaptation mechanisms to hypoxia, 16 healthy men (aged 20-28 years) were studied through magnetic resonance imaging (MRI) under room air conditions, short-term-hypoxia (7 minutes before and during the MRI scan), and long-term hypoxia (8.5 hours before and during the MRI scan). Oxygen saturation was continuously measured using a finger-mounted pulse oximeter. Two independent blinded readers compared the 3 scans of each participant and graded the SWAN source images and minimum intensity projections according to the size, number, and signal intensity of the Cerebral Veins. Signal intensities of deep Cerebral Veins were measured, and signal intensity proportions of deep Cerebral Veins to different parenchymal brain regions were calculated. RESULTS: Nine subjects could be included in the study. In all of them, both readers correctly distinguished the 2 hypoxia scans from the baseline scan, grading the SWAN images acquired under hypoxic conditions as visualizing Cerebral Veins more prominently. Signal intensities of the deep Cerebral Veins and signal intensity proportions were significantly lower in the hypoxia scans. No significant differences between short-term and long-term hypoxia were found on visual inspections and signal intensity measurements. This correlated with the results of the pulse oximetry: mean O2 saturation values were 97.9% ± 1.2% (baseline), 84.1% ± 3.8% (short-term hypoxia), and 82.8% ± 4.4% (long-term hypoxia), respectively. CONCLUSIONS: Hypoxia leads to visible and measurable changes in Cerebral Veins as depicted through SWAN. Possible clinical implications of this finding include stroke and tumor imaging and need further investigation.
Bilge Oztoprak - One of the best experts on this subject based on the ideXlab platform.
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prominent Cerebral Veins on susceptibility weighted imaging swi in pulmonary embolism
European Radiology, 2017Co-Authors: Bilge OztoprakAbstract:Objectives Clinical applications of susceptibility-weighted imaging (SWI) are increasing steadily. The aim of this study is to investigate the appearance of Cerebral Veins on SWI, which is very sensitive to the deoxyhaemoglobin level in vessels, in pulmonary embolism (PE).
Jennifer Linn - One of the best experts on this subject based on the ideXlab platform.
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susceptibility weighted angiography swan of Cerebral Veins and arteries compared to tof mra
European Journal of Radiology, 2012Co-Authors: Tobias Boeckhbehrens, Juergen Lutz, N Lummel, Michael Burke, T Wesemann, Veronika Schopf, H Bruckmann, Jennifer LinnAbstract:Abstract Problem High resolution, non-contrast imaging of both Cerebral Veins and arteries by use of gradient echo T2 star weighted angiography (SWAN) is a new method for susceptibility-weighted imaging with short acquisition times. We assessed the potential of this sequence for the depiction of both Cerebral Veins and arteries. Methods 15 healthy volunteers were included in the study. MRI was performed on a 3 T MR scanner using the following sequences: (1) a 3D multi-echo gradient echo T2 star weighted angiography (SWAN), (2) an arterial 3D TOF MR angiography and (3) a venous 2D TOF. With regard to the SWAN sequence, both MinIP and MIP images were reconstructed and systematically compared to MIP reconstructions of the artTOF and the venTOF. To suggest possible clinical implications of our findings, we additionally included two illustrative cases. Results With regard to the visualization of the Cerebral Veins, the MinIP reconstructions of the SWAN sequence were considerably superior compared to the venTOF. Concerning the depiction of the main segments of the big Cerebral arteries the value of the MIP reconstructions of the SWAN was comparable to that of the artTOF with limitations in the homogenity and in the depiction of smaller arteries. Conclusions SWAN allows for high-resolution visualization of both Cerebral Veins and arteries in one sequence without application of contrast agent and with significantly shortened scan time compared to the combined scan time of TOF-MRA and TOF-MRV. By use of either MinIP or MIP reconstructions, the arteries can be distinguished from the Veins.
Maximilian Patzig - One of the best experts on this subject based on the ideXlab platform.
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susceptibility weighted angiography visualizes hypoxia in Cerebral Veins
Investigative Radiology, 2015Co-Authors: Maximilian Patzig, Berend Feddersen, Katrin Haegler, Bernhard Olzowy, Klaus Mees, Rainald Fischer, Sven Becker, Ulrich Kisser, Jessica Freiherr, Rupert GrasheyAbstract:OBJECTIVES: The objective of this study was to evaluate the influence of short- and long-term hypoxia on the depiction of Cerebral Veins in the susceptibility-weighted angiography (SWAN) sequence. MATERIALS AND METHODS: In the context of a study on brain adaptation mechanisms to hypoxia, 16 healthy men (aged 20-28 years) were studied through magnetic resonance imaging (MRI) under room air conditions, short-term-hypoxia (7 minutes before and during the MRI scan), and long-term hypoxia (8.5 hours before and during the MRI scan). Oxygen saturation was continuously measured using a finger-mounted pulse oximeter. Two independent blinded readers compared the 3 scans of each participant and graded the SWAN source images and minimum intensity projections according to the size, number, and signal intensity of the Cerebral Veins. Signal intensities of deep Cerebral Veins were measured, and signal intensity proportions of deep Cerebral Veins to different parenchymal brain regions were calculated. RESULTS: Nine subjects could be included in the study. In all of them, both readers correctly distinguished the 2 hypoxia scans from the baseline scan, grading the SWAN images acquired under hypoxic conditions as visualizing Cerebral Veins more prominently. Signal intensities of the deep Cerebral Veins and signal intensity proportions were significantly lower in the hypoxia scans. No significant differences between short-term and long-term hypoxia were found on visual inspections and signal intensity measurements. This correlated with the results of the pulse oximetry: mean O2 saturation values were 97.9% ± 1.2% (baseline), 84.1% ± 3.8% (short-term hypoxia), and 82.8% ± 4.4% (long-term hypoxia), respectively. CONCLUSIONS: Hypoxia leads to visible and measurable changes in Cerebral Veins as depicted through SWAN. Possible clinical implications of this finding include stroke and tumor imaging and need further investigation.
Shoki Takahashi - One of the best experts on this subject based on the ideXlab platform.
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preoperative evaluation of the deep Cerebral Veins using 3 tesla magnetic resonance imaging
Minimally Invasive Neurosurgery, 2011Co-Authors: Ryuta Saito, Shuichi Higano, Toshihiro Kumabe, Shoki Takahashi, Masayuki Kanamori, Yoji Yamashita, Yukihiko Sonoda, Teiji TominagaAbstract:BACKGROUND: Surgical treatment of deep-seated tumors such as supratentorial intraventricular and thalamic-pineal-tectal region tumors carries a risk of postoperative deficits due to possible damage to deep Cerebral Veins including the internal Cerebral vein. It is often difficult to identify whether the vessel encountered during surgery needs to be preserved or not through the small operative field. Therefore, preoperative evaluation of deep venous structures is important. We evaluated the usefulness of 3-Tesla magnetic resonance imaging (3 T MRI) for this purpose. METHODS: First, the ability to detect deep venous structures was compared with both 3-dimensional computed tomographical angiography (3D-CTA) and 3 T MRI in patients without any damage to deep venous structures. Images of 7 consecutive patients suffering from insulo-opercular gliomas who underwent both imaging modes for the identification of lateral striate arteries were reconstructed for evaluation of the deep Cerebral Veins. Subsequently, surgery for tumors at the supratentorial intraventricular and thalamic-pineal-tectal regions was prospectively performed with preoperative evaluation of deep venous system only using 3 T MRI. RESULTS: Information on the deep venous systems acquired by 3 T MRI was as useful as that acquired by 3D-CTA. Until today, we have treated 8 cases of supratentorial intraventricular and thalamic-pineal-tectal region tumors with preoperative evaluation of the deep venous system using 3 T MRI without any morbidity. CONCLUSION: Information on the deep venous system obtained with 3 T MRI aids the surgery of supratentorial intraventricular and thalamic-pineal-tectal region tumors. As the required sequences of 3 T MRI are same as those necessary for the neuronavigation system, and 3 T MRI can be achieved without the use of iodine-based contrast agents, 3 T MRI can be an alternative for preoperative evaluation of the deep venous systems.
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virtually peeling off the skull and scalp a simple way of mapping the superficial Cerebral Veins on the brain surface
Stereotactic and Functional Neurosurgery, 2008Co-Authors: Xiangyang Gong, Shuichi Higano, Shunji Mugikura, Atsushi Umetsu, Takaki Murata, Toshihiro Kumabe, Shoki TakahashiAbstract:Purpose: A simple MRI postprocessing technique was developed to display superficial Cerebral Veins (SCVs) along with brain surface structures. Materials and Methods:
